With the increased mechanization in horticulture it is important to manage the processing conditions for the plants as well as possible. One condition which has been poorly managed heretofore is the moisture content of growing substrate such as potting soil. When wholly artificial substrates such as mineral wool and the like are used, it is possible to properly determine and manage the moisture content thereof. In the case of potting soil and mixtures of potting soil this is however much more difficult; the composition of the potting soil is much more heterogeneous and moreover varies, while the water-retaining properties of potting soil are difficult to establish. The water content of potting soil is moreover highly variable, particularly if it has been stored for some time in the outside air.
There therefore exists a need for a method and apparatus for determining the moisture content of potting soil. There is furthermore a need for a method and an apparatus for correcting the moisture content, in particular for increasing the moisture content to a predetermined value.